Preheat the grill to high and grill the hot dog buns until golden brown. Place two slices of cheese on each bun, slightly overlapping the edges of the buns. Place back under the grill until the cheese melts, then set aside.

Preheat the oven to 150˚C/130˚C fan/gas mark 2.

Heat a large non-stick pan over a medium-high heat and add two-thirds of the butter. Cook the onion and pepper for 5-8 minutes until soft. Remove and set aside.

Add the remaining butter and turn the heat to high. Season the steak very generously with salt and pepper and add to the hot pan. Turn the heat to medium-high and cook the steak for 2-3 minutes, stirring.

Divide the meat and vegetables between the buns and wrap each one in a separate square of tin foil. Place in the oven for 7-10 minutes to warm through. Serve piping hot with chips.